Athenaeus 'Mechanicus' - the surname differentiates him from better-known homonyms - wrote a treatise on Greek siege-machinery. Uniquely in the genre, it combined general cultural erudition, historical survey, and This is the work's first English translation, and the first commentary in any language. Athenaeus is argued to be a Cilician ex-statesman living in Rome in the 20s B.C. and striving, like his contemporary Vitruvius, for imperial patronage there.As regards the treatise itself, it is here evaluated from the perspectives not only of ancient history and philology but also engineering. This highlights the skill of an early-Hellenistic practitioner like Diades, who served Alexander the Great; but it also reveals how, in a later age, workable ideas could no longer be distinguished from wishful thinking - the latter a category to which Athenaeus himself proudly made his own contributions.